This invention relates generally to a specimen holder and more particularly to a specimen holder of the type used with an X-ray diffractometer or the like.
The study of structural properties of substances which are sensitive to air and/or moisture through X-ray diffraction spectrometry using a diffractometer or goniometer necessitates sealing enclosure of the substance prior to mounting on the diffractometer or goniometer. Enclosure of the substance in a capillary tube to protect it from air or moisture is unsatisfactory, particularly for the study of large surface area samples (e.g., samples having a surface area greater than about 2 to 3 square millimeters). The problem of crystallographic investigation of large surface area samples has become more acute with the increasing production of materials in the form of a thin film. Limited investigations of large surface area samples can be carried out using a small crystal or powder enclosed in a capillary tube with a full or half circle goniometer, which allows rotation of the capillary tube. However, full and half circle goniometers are expensive and simply not available to many researchers. In order to simulate large surface area geometry for study with a diffractometer, a researcher must engage in the arduous task of preparing and arranging a row of capillaries. Whether a full or half circle goniometer, or a diffractometer is used, the structural information which can be obtained is less complete than that which can be obtained through examination of a large surface area sample.
A large surface area sample may also be encased in an overlayer of mylar, or the like. However, at low angles of X-ray incidence on the sample, the mylar absorption of radiation (because of the increased thickness of mylar through which the radiation must pass) interferes with the readings obtained.
Vacuum tight specimen holders, which are typically used in high temperature studies, are presently available. These holders typically include a housing having a specimen holding chamber, one wall of which is defined by a hemi-cylindrical window made of material which transmit x-radiation from the diffractometer. The windows are typically made of aluminum or beryllium foil, which are suitably X-ray transmissive and temperature resistant, but which are relatively fragile. Moreover, these high temperature holders are large and cumbersome to handle and mount on a goniometer or diffractometer. Frequently, a substantial modification must be made to the diffractometer or goniometer in order to mount the holder. Disposition of an air or moisture sensitive sample in the housing is difficult because the sample must be transferred from a glove box or other air tight container to the holder. Moreover, a skilled researcher may spend an hour or more aligning the specimen before any data can be acquired.